64-bit support for code analysis has been added to VS11 beta. You do have to use toolset v110 in order to get this support. Regarding the issue you ran into that code analysis doesn't report any results on both 32-bit and 64-bit, I can't tell what the exact problem is from the description you provided. The code you mentioned should invoke code analysis results. Do you mind sharing with us your test project so we can investigate? You can send it to my mailbox ronglu at microsoft.com.
Thanks and Best regards,
Visual Studio team